Integrating mirrored storage to remote replication site

A computer system comprising:

• one or more processors, one or more computer-readable memories, one or more computer-readable tangible storage media, and program instructions stored on at least one of the one or more computer-readable tangible storage media for execution by at least one of the one or more processors to cause the computer system to:
• store a volume of data in a dual-site data replication system comprising a first site and a second site, the first site comprising a first disk and the second site comprising a second disk, the dual-site data replication system providing active-active access to the volume of data stored in one of the first disk or the second disk that is designated as an active disk for the active-active access and replicated in the other of the first disk and the second disk that is designated as a backup disk for the active-active access;
• swap designations of the active disk and the backup disk between the first disk at the first site and the second disk at the second site in response to detection of a condition;
• in response to the swapping, update in a storage descriptor area of the first disk or of the second disk at least one indicator that indicates whether the first disk is designated as the active disk or as the backup disk for the active-active access;
• transmit a query command to access the updated storage descriptor area;
• receive a response to the query command, the response comprising a current designation of the active disk and the backup disk for the dual-site data replication system and being generated in response to checking the at least one updated indicator;
• and
• in response to the receiving the response to the query command, control an additional copy of the volume of data at a third site, wherein the controlling is based on the active disk as determined by the current designation in the response.

A computer program product comprising a computer-readable storage medium having program instructions embodied therewith, wherein the program instructions are executable by a computer system to cause the computer system to:

• store a volume of data in a dual-site data replication system comprising a first site and a second site, the first site comprising a first disk and the second site comprising a second disk, the dual-site data replication system providing active-active access to the volume of data stored in one of the first disk or the second disk that is designated as an active disk for the active-active access and replicated in the other of the first disk and the second disk that is designated as a backup disk for the active-active access;
• swap designations of the active disk and the backup disk between the first disk at the first site and the second disk at the second site in response to detection of a condition;
• in response to the swapping, update in a storage descriptor area of the first disk or the second disk at least one indicator that indicates whether the first disk is designated as the active disk or as the backup disk for the active-active access;
• transmit a query command to access the updated storage descriptor area;
• receive a response to the query command, the response comprising a current designation of the active disk and the backup disk for the dual-site data replication system;
• and
• in response to the receiving the response to the query command, control an additional copy of the volume of data at a third site, wherein the controlling is based on the active disk as determined by the current designation in the response.